This invention relates to devices for sharpening scissors and is particularly concerned with such devices which are able to sharpen both scissor blades in a single operation. It is to be understood that the term "scissors" is used as a general term for pivoted blade cutting instruments and consequently the invention extends to devices for sharpening shears, for example.
Scissor sharpeners of the foregoing kind are generally arranged so that the sharpening action occurs in the longitudinal direction of the scissor blades, and one such device forms the subject of U.S. Pat. No. 4,348,809. The sharpening action produces minute grooves or striations in the longitudinal edge surfaces of the blades over which the sharpening elements move, and those striations extend in the longitudinal direction of the respective blade. Such longitudinal striations can adversely affect the operation of the scissors in some circumstances because they promote relative slippage between the scissor blades and an article or object engaged between those blades.
Whenever an article or object is being cut by scissors, a component of the forces generated by that cutting action will tend to push the article or object towards the tip end of the blades. Longitudinal striations as referred to above facilitate such relative movement or slippage and can therefore make it difficult to cut some objects, and particularly relatively thick objects. Manicure scissors, for example, can be difficult to use if the longitudinal working edges of the blades have longitudinally extending striations.
It is an object of the present invention to provide a scissors sharpener which is operative to simultaneously sharpen both blades and which does not produce longitudinal striations in the course of the sharpening operation. It is another object of the invention to provide such a sharpener which forms part of a scabbard or storage container for scissors.
A sharpener according to the invention is designed for use with scissors of the general kind described in U.S. Pat. No. 4,279,076. Such scissors have two blades arranged so that in the closed condition the cutting edge of each blade is either substantially coincident with the back edge of the other blade, or is located beyond that back edge. That is, each cutting edge forms a respective longitudinal boundary of the closed blade assembly, and it is that feature which enables convenient simultaneous sharpening of the two blades.